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1.
Cell ; 187(3): 750-763.e20, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38242132

RESUMO

Breastfeeding offers demonstrable benefits to newborns and infants by providing nourishment and immune protection and by shaping the gut commensal microbiota. Although it has been appreciated for decades that breast milk contains complement components, the physiological relevance of complement in breast milk remains undefined. Here, we demonstrate that weanling mice fostered by complement-deficient dams rapidly succumb when exposed to murine pathogen Citrobacter rodentium (CR), whereas pups fostered on complement-containing milk from wild-type dams can tolerate CR challenge. The complement components in breast milk were shown to directly lyse specific members of gram-positive gut commensal microbiota via a C1-dependent, antibody-independent mechanism, resulting in the deposition of the membrane attack complex and subsequent bacterial lysis. By selectively eliminating members of the commensal gut community, complement components from breast milk shape neonate and infant gut microbial composition to be protective against environmental pathogens such as CR.


Assuntos
Proteínas do Sistema Complemento , Microbioma Gastrointestinal , Leite , Animais , Feminino , Humanos , Lactente , Camundongos , Bactérias , Aleitamento Materno , Citrobacter rodentium , Proteínas do Sistema Complemento/análise , Fatores Imunológicos , Saúde do Lactente , Leite Humano , Leite/química , Infecções por Enterobacteriaceae/imunologia
2.
Proc Natl Acad Sci U S A ; 120(7): e2201076120, 2023 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-36749728

RESUMO

Sea turtles represent an ancient lineage of marine vertebrates that evolved from terrestrial ancestors over 100 Mya. The genomic basis of the unique physiological and ecological traits enabling these species to thrive in diverse marine habitats remains largely unknown. Additionally, many populations have drastically declined due to anthropogenic activities over the past two centuries, and their recovery is a high global conservation priority. We generated and analyzed high-quality reference genomes for the leatherback (Dermochelys coriacea) and green (Chelonia mydas) turtles, representing the two extant sea turtle families. These genomes are highly syntenic and homologous, but localized regions of noncollinearity were associated with higher copy numbers of immune, zinc-finger, and olfactory receptor (OR) genes in green turtles, with ORs related to waterborne odorants greatly expanded in green turtles. Our findings suggest that divergent evolution of these key gene families may underlie immunological and sensory adaptations assisting navigation, occupancy of neritic versus pelagic environments, and diet specialization. Reduced collinearity was especially prevalent in microchromosomes, with greater gene content, heterozygosity, and genetic distances between species, supporting their critical role in vertebrate evolutionary adaptation. Finally, diversity and demographic histories starkly contrasted between species, indicating that leatherback turtles have had a low yet stable effective population size, exhibit extremely low diversity compared with other reptiles, and harbor a higher genetic load compared with green turtles, reinforcing concern over their persistence under future climate scenarios. These genomes provide invaluable resources for advancing our understanding of evolution and conservation best practices in an imperiled vertebrate lineage.


Assuntos
Tartarugas , Animais , Ecossistema , Dinâmica Populacional
3.
Stat Med ; 42(13): 2257-2273, 2023 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-36999745

RESUMO

Accurate and efficient detection of ovarian cancer at early stages is critical to ensure proper treatments for patients. Among the first-line modalities investigated in studies of early diagnosis are features distilled from protein mass spectra. This method, however, considers only a specific subset of spectral responses and ignores the interplay among protein expression levels, which can also contain diagnostic information. We propose a new modality that automatically searches protein mass spectra for discriminatory features by considering the self-similar nature of the spectra. Self-similarity is assessed by taking a wavelet decomposition of protein mass spectra and estimating the rate of level-wise decay in the energies of the resulting wavelet coefficients. Level-wise energies are estimated in a robust manner using distance variance, and rates are estimated locally via a rolling window approach. This results in a collection of rates that can be used to characterize the interplay among proteins, which can be indicative of cancer presence. Discriminatory descriptors are then selected from these evolutionary rates and used as classifying features. The proposed wavelet-based features are used in conjunction with features proposed in the existing literature for early stage diagnosis of ovarian cancer using two datasets published by the American National Cancer Institute. Including the wavelet-based features from the new modality results in improvements in diagnostic performance for early-stage ovarian cancer detection. This demonstrates the ability of the proposed modality to characterize new ovarian cancer diagnostic information.


Assuntos
Neoplasias Ovarianas , Análise de Ondaletas , Humanos , Feminino , Neoplasias Ovarianas/diagnóstico , Diagnóstico Precoce , Algoritmos
4.
J Biosoc Sci ; 55(5): 812-852, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-36814332

RESUMO

Communities urbanize when the net benefits to urbanization exceed rural areas. Body mass, height, and weight are biological welfare measures that reflect the net difference between calories consumed and calories required for work and to withstand the physical environment. Individuals of African-decent had greater BMIs, heavier weights, and shorter statures. Urban farmers had lower BMIs, shorter statures, and lower weight than rural farmers. Over the late 19th and early 20th centuries, urban and rural BMIs, height, and weight were constant, and rural farmers had greater BMIs, taller statures, and heavier weights than urban farmers and workers in other occupations.


Assuntos
Índice de Massa Corporal , População Rural , População Urbana , Urbanização , Humanos , Negro ou Afro-Americano , Peso Corporal , Estados Unidos , Fazendeiros
5.
Appl Opt ; 61(22): 6627-6641, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-36255889

RESUMO

The first, to our knowledge, successful laboratory implementation of an approach to image winds using simultaneous (as opposed to sequential) fringe imaging of suitable isolated spectral emission lines is described. Achieving this in practice has been a long-standing goal for wind imaging using airglow. It avoids the aliasing effects of source irradiance variations that are possible with sequential fringe sampling techniques. Simultaneous fringe imaging is accomplished using a field-widened Michelson interferometer by depositing phase steps on four quadrants of one of the mirrors and designing an optical system so that four images of the scene of interest, each at a different phase, are simultaneously produced. In this paper, the instrument characteristics, its characterization, and the analysis algorithms necessary for use of the technique for this type of interferometer are described for the first time, to the best of our knowledge. The large throughput associated with field-widened Michelson interferometers is sufficient for the spatial resolutions and temporal cadences necessary for ground based imaging of gravity waves in wind and irradiance to be achieved. The practical demonstration of this technique also validates its use for proposed monolithic satellite instruments for wind measurements using airglow on the Earth and Mars.

6.
J Biosoc Sci ; 54(4): 583-604, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-34167598

RESUMO

When other measures for material conditions are scarce or unreliable, the use of height is now common to evaluate economic conditions during economic development. However, throughout US economic development, height data by gender have been slow to emerge. Throughout the late 19th and early 20th centuries, female and male statures remained constant. Agricultural workers had taller statures than workers in other occupations, and the female agricultural height premium was over twice that of males. For both females and males, individuals with fairer complexions were taller than their darker complexioned counterparts. Gender collectively had the greatest explanatory effect associated with stature, followed by age and nativity. Socioeconomic status and birth period had the smallest collective effects with stature.


Assuntos
Estatura , Estado Nutricional , Desenvolvimento Econômico , Feminino , História do Século XIX , Humanos , Masculino , Ocupações , Classe Social
7.
Microbiology (Reading) ; 167(10)2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34661520

RESUMO

Uroporphyrinogen III, the universal progenitor of macrocyclic, modified tetrapyrroles, is produced from aminolaevulinic acid (ALA) by a conserved pathway involving three enzymes: porphobilinogen synthase (PBGS), hydroxymethylbilane synthase (HmbS) and uroporphyrinogen III synthase (UroS). The gene encoding uroporphyrinogen III synthase has not yet been identified in Plasmodium falciparum, but it has been suggested that this activity is housed inside a bifunctional hybroxymethylbilane synthase (HmbS). Additionally, an unknown protein encoded by PF3D7_1247600 has also been predicted to possess UroS activity. In this study it is demonstrated that neither of these proteins possess UroS activity and the real UroS remains to be identified. This was demonstrated by the failure of codon-optimized genes to complement a defined Escherichia coli hemD- mutant (SASZ31) deficient in UroS activity. Furthermore, HPLC analysis of the oxidized reaction product from recombinant, purified P. falciparum HmbS showed that only uroporphyrin I could be detected (corresponding to hydroxymethylbilane production). No uroporphyrin III was detected, showing that P. falciparum HmbS does not have UroS activity and can only catalyze the formation of hydroxymethylbilane from porphobilinogen.


Assuntos
Heme/biossíntese , Hidroximetilbilano Sintase/metabolismo , Plasmodium falciparum/enzimologia , Vias Biossintéticas , Escherichia coli/genética , Teste de Complementação Genética , Hidroximetilbilano Sintase/genética , Mutação , Plasmodium falciparum/genética , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Uroporfirinogênio III Sintetase/genética , Uroporfirinogênio III Sintetase/metabolismo , Uroporfirinogênios/metabolismo
8.
Histochem Cell Biol ; 155(2): 279-289, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33515079

RESUMO

The alveolar ducts are connected to peripheral septal fibers which extend from the visceral pleura into interlobular septa, and are anchored to axial fibers in the small airways. Together these axial and septal fibers constitute a fiber continuum that provides tension and integrity throughout the lung. Building on the observations that alveolar ducts associated with sub-pleural alveoli are orientated perpendicular to the visceral pleura, and in parallel to each other, the goal of the present study was to investigate the nature of the collagen fiber organization within sub-pleural alveolar ducts in healthy control and elastase-induced emphysema murine lungs. Employing three-dimensional second harmonic generation imaging, the structural arrangement of fibrilar collagen fibers could be visualized in cleared murine lungs. In healthy control lungs, fibrilar collagen fibers within alveolar mouths formed the coiled collagen structure within the alveolar duct. In the elastase-treated emphysema lungs, there was loss of fibrilar collagen fibers (p < 0.01) and disruption of collagens structural organization as measured by the fibrillar collagen length (p < 0.01) and entropy (p < 0.01). Compared to the alveolar ducts from healthy controls, there was a significant increase in the area of cells (nm2, p < 0.001), and area of cells with cytoplasmic granules (nm2, p < 0.001) compared to emphysematous lungs. These results are consistent with the idea that one of the major contributors to the progressive loss of alveolar surfaces and elastic recoil in the emphysematous lung is loss of the structural integrity of the collagen scaffold that maintains the spatial relationships important for cell survival and lung function.


Assuntos
Colágeno/análise , Alvéolos Pulmonares/química , Enfisema Pulmonar/diagnóstico por imagem , Microscopia de Geração do Segundo Harmônico , Animais , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Alvéolos Pulmonares/metabolismo , Enfisema Pulmonar/metabolismo , Suínos
9.
Am J Med Genet A ; 185(11): 3259-3265, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34169650

RESUMO

Victor McKusick's many contributions to medicine are legendary, but his magnum opus is Mendelian Inheritance in Man (MIM), his catalog of Mendelian phenotypes and their associated genes. The catalog, originally published in 1966 in book form, became available on the internet as Online Mendelian Inheritance in Man (OMIM®) in 1987. The first of 12 editions of MIM included 1486 entries; this number has increased to over 25,000 entries in OMIM as of April 2021, which demonstrates the growth of knowledge about Mendelian phenotypes and their genes through the years. OMIM now has over 20,000 unique users a day, including users from every country in the world. Many of the early decisions made by McKusick, such as to maintain MIM data in a computer-readable format, to separate phenotype entries from those for genes, and to give phenotypes and genes MIM numbers, have proved essential to the long-term utility and flexibility of his catalog. Based on his extensive knowledge of genetics and vision of its future in the field of medicine, he developed a framework for the capture and summary of information from the published literature on phenotypes and their associated genes; this catalog continues to serve as an indispensable resource to the genetics community.


Assuntos
Bases de Dados Genéticas/história , Genética Médica/história , Mapeamento Cromossômico , História do Século XX , História do Século XXI , Humanos
10.
J Hered ; 112(6): 540-548, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34146095

RESUMO

The Puma lineage within the family Felidae consists of 3 species that last shared a common ancestor around 4.9 million years ago. Whole-genome sequences of 2 species from the lineage were previously reported: the cheetah (Acinonyx jubatus) and the mountain lion (Puma concolor). The present report describes a whole-genome assembly of the remaining species, the jaguarundi (Puma yagouaroundi). We sequenced the genome of a male jaguarundi with 10X Genomics linked reads and assembled the whole-genome sequence. The assembled genome contains a series of scaffolds that reach the length of chromosome arms and is similar in scaffold contiguity to the genome assemblies of cheetah and puma, with a contig N50 = 100.2 kbp and a scaffold N50 = 49.27 Mbp. We assessed the assembled sequence of the jaguarundi genome using BUSCO, aligned reads of the sequenced individual and another published female jaguarundi to the assembled genome, annotated protein-coding genes, repeats, genomic variants and their effects with respect to the protein-coding genes, and analyzed differences of the 2 jaguarundis from the reference mitochondrial genome. The jaguarundi genome assembly and its annotation were compared in quality, variants, and features to the previously reported genome assemblies of puma and cheetah. Computational analyzes used in the study were implemented in transparent and reproducible way to allow their further reuse and modification.


Assuntos
Felidae , Puma , Animais , Feminino , Genoma , Genômica , Masculino , Anotação de Sequência Molecular , Puma/genética
11.
Nucleic Acids Res ; 47(D1): D1038-D1043, 2019 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-30445645

RESUMO

For over 50 years Mendelian Inheritance in Man has chronicled the collective knowledge of the field of medical genetics. It initially cataloged the known X-linked, autosomal recessive and autosomal dominant inherited disorders, but grew to be the primary repository of curated information on both genes and genetic phenotypes and the relationships between them. Each phenotype and gene is given a separate entry assigned a stable, unique identifier. The entries contain structured summaries of new and important information based on expert review of the biomedical literature. OMIM.org provides interactive access to the knowledge repository, including genomic coordinate searches of the gene map, views of genetic heterogeneity of phenotypes in Phenotypic Series, and side-by-side comparisons of clinical synopses. OMIM.org also supports computational queries via a robust API. All entries have extensive targeted links to other genomic resources and additional references. Updates to OMIM can be found on the update list or followed through the MIMmatch service. Updated user guides and tutorials are available on the website. As of September 2018, OMIM had over 24,600 entries, and the OMIM Morbid Map Scorecard had 6,259 molecularized phenotypes connected to 3,961 genes.


Assuntos
Biologia Computacional/métodos , Bases de Dados Genéticas , Doenças Genéticas Inatas/genética , Predisposição Genética para Doença/genética , Armazenamento e Recuperação da Informação/métodos , Estudos de Associação Genética/métodos , Genética Médica/métodos , Genômica/métodos , Humanos , Padrões de Herança/genética , Internet
12.
Molecules ; 26(14)2021 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-34299465

RESUMO

Lytic transglycosylases such as Slt35 from E. coli are enzymes involved in bacterial cell wall remodelling and recycling, which represent potential targets for novel antibacterial agents. Here, we investigated a series of known glycosidase inhibitors for their ability to inhibit Slt35. While glycosidase inhibitors such as 1-deoxynojirimycin, castanospermine, thiamet G and miglitol had no effect, the phenothiazinium dye thionine acetate was found to be a weak inhibitor. IC50 values and binding constants for thionine acetate were similar for Slt35 and the hen egg white lysozyme. Molecular docking simulations suggest that thionine binds to the active site of both Slt35 and lysozyme, although it does not make direct interactions with the side-chain of the catalytic Asp and Glu residues as might be expected based on other inhibitors. Thionine acetate also increased the potency of the beta-lactam antibiotic ampicillin against a laboratory strain of E. coli.


Assuntos
Glicosiltransferases/metabolismo , Fenotiazinas/farmacologia , Acetatos/metabolismo , Sequência de Aminoácidos/genética , Proteínas de Bactérias/química , Sítios de Ligação/genética , Domínio Catalítico/genética , Parede Celular/metabolismo , Cristalografia por Raios X/métodos , Escherichia coli/metabolismo , Proteínas de Escherichia coli/efeitos dos fármacos , Proteínas de Escherichia coli/metabolismo , Glicosiltransferases/antagonistas & inibidores , Glicosiltransferases/efeitos dos fármacos , Modelos Moleculares , Simulação de Acoplamento Molecular , Muramidase/antagonistas & inibidores , Muramidase/metabolismo , Peptidoglicano/metabolismo , Fenotiazinas/metabolismo , Conformação Proteica/efeitos dos fármacos
13.
Br J Hist Sci ; 54(2): 155-175, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33739248

RESUMO

This article presents a case study of life and work at the Royal Observatory at Greenwich (1835-1933) which reveals tensions between the lived reality of the observatory as a social space, and the attempts to create order, maintain discipline and project an image of authority in order to ensure the observatory's long-term stability. Domestic, social and scientific activities all intermingled within the observatory walls in ways which were occasionally disorderly. But life at Greenwich was carefully managed to stave off such disorder and to maintain an appearance of respectability which was essential to the observatory's reputation and output. The article focuses on three areas of management: (1) the observatory's outer boundaries, demonstrating how Greenwich navigated both human and environmental intrusions from the wider world; (2) the house, examining how Greenwich's domestic spaces provided stability, while also complicating observatory life via the management of domestic servants; and (3) the scientific spaces, with an emphasis on the work and play of the observatory's boy computers. Together, these three parts demonstrate that the stability of the observatory was insecure, despite being perpetuated via powerful physical and social boundaries. It had to be continually maintained, and was regularly challenged by Greenwich's occupants and neighbours.

14.
Genet Epidemiol ; 43(1): 37-49, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30246882

RESUMO

We previously demonstrated how sharing of rare variants (RVs) in distant affected relatives can be used to identify variants causing a complex and heterogeneous disease. This approach tested whether single RVs were shared by all sequenced affected family members. However, as with other study designs, joint analysis of several RVs (e.g., within genes) is sometimes required to obtain sufficient statistical power. Further, phenocopies can lead to false negatives for some causal RVs if complete sharing among affected is required. Here, we extend our methodology (Rare Variant Sharing, RVS) to address these issues. Specifically, we introduce gene-based analyses, a partial sharing test based on RV sharing probabilities for subsets of affected relatives and a haplotype-based RV definition. RVS also has the desirable feature of not requiring external estimates of variant frequency or control samples, provides functionality to assess and address violations of key assumptions, and is available as open source software for genome-wide analysis. Simulations including phenocopies, based on the families of an oral cleft study, revealed the partial and complete sharing versions of RVS achieved similar statistical power compared with alternative methods (RareIBD and the Gene-Based Segregation Test), and had superior power compared with the pedigree Variant Annotation, Analysis, and Search Tool (pVAAST) linkage statistic. In studies of multiplex cleft families, analysis of rare single nucleotide variants in the exome of 151 affected relatives from 54 families revealed no significant excess sharing in any one gene, but highlighted different patterns of sharing revealed by the complete and partial sharing tests.


Assuntos
Predisposição Genética para Doença , Variação Genética , Linhagem , Análise de Sequência de DNA , Fissura Palatina/genética , Simulação por Computador , Exoma/genética , Heterogeneidade Genética , Haplótipos/genética , Humanos , Modelos Genéticos , Fenótipo , Probabilidade , Fatores de Risco , Sequenciamento do Exoma
15.
Am J Hum Genet ; 100(6): 895-906, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28552198

RESUMO

With advances in genomic sequencing technology, the number of reported gene-disease relationships has rapidly expanded. However, the evidence supporting these claims varies widely, confounding accurate evaluation of genomic variation in a clinical setting. Despite the critical need to differentiate clinically valid relationships from less well-substantiated relationships, standard guidelines for such evaluation do not currently exist. The NIH-funded Clinical Genome Resource (ClinGen) has developed a framework to define and evaluate the clinical validity of gene-disease pairs across a variety of Mendelian disorders. In this manuscript we describe a proposed framework to evaluate relevant genetic and experimental evidence supporting or contradicting a gene-disease relationship and the subsequent validation of this framework using a set of representative gene-disease pairs. The framework provides a semiquantitative measurement for the strength of evidence of a gene-disease relationship that correlates to a qualitative classification: "Definitive," "Strong," "Moderate," "Limited," "No Reported Evidence," or "Conflicting Evidence." Within the ClinGen structure, classifications derived with this framework are reviewed and confirmed or adjusted based on clinical expertise of appropriate disease experts. Detailed guidance for utilizing this framework and access to the curation interface is available on our website. This evidence-based, systematic method to assess the strength of gene-disease relationships will facilitate more knowledgeable utilization of genomic variants in clinical and research settings.


Assuntos
Estudos de Associação Genética , Predisposição Genética para Doença , Genômica , Humanos , Reprodutibilidade dos Testes
16.
Bioinformatics ; 35(4): 571-578, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30084993

RESUMO

MOTIVATION: De novo copy number deletions have been implicated in many diseases, but there is no formal method to date that identifies de novo deletions in parent-offspring trios from capture-based sequencing platforms. RESULTS: We developed Minimum Distance for Targeted Sequencing (MDTS) to fill this void. MDTS has similar sensitivity (recall), but a much lower false positive rate compared to less specific CNV callers, resulting in a much higher positive predictive value (precision). MDTS also exhibited much better scalability. AVAILABILITY AND IMPLEMENTATION: MDTS is freely available as open source software from the Bioconductor repository. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Algoritmos , Variações do Número de Cópias de DNA , Deleção de Sequência , Software , Biologia Computacional
17.
Am J Hum Genet ; 98(4): 709-27, 2016 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-27058444

RESUMO

The genetic mechanisms underlying the poor prognosis of esophageal squamous cell carcinoma (ESCC) are not well understood. Here, we report somatic mutations found in ESCC from sequencing 10 whole-genome and 57 whole-exome matched tumor-normal sample pairs. Among the identified genes, we characterized mutations in VANGL1 and showed that they accelerated cell growth in vitro. We also found that five other genes, including three coding genes (SHANK2, MYBL2, FADD) and two non-coding genes (miR-4707-5p, PCAT1), were involved in somatic copy-number alterations (SCNAs) or structural variants (SVs). A survival analysis based on the expression profiles of 321 individuals with ESCC indicated that these genes were significantly associated with poorer survival. Subsequently, we performed functional studies, which showed that miR-4707-5p and MYBL2 promoted proliferation and metastasis. Together, our results shed light on somatic mutations and genomic events that contribute to ESCC tumorigenesis and prognosis and might suggest therapeutic targets.


Assuntos
Carcinogênese/genética , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/genética , Neoplasias Esofágicas/diagnóstico , Neoplasias Esofágicas/genética , Regulação Neoplásica da Expressão Gênica , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Proteínas de Transporte/genética , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Variações do Número de Cópias de DNA , Carcinoma de Células Escamosas do Esôfago , Exoma , Proteína de Domínio de Morte Associada a Fas/genética , Feminino , Perfilação da Expressão Gênica , Estudos de Associação Genética , Humanos , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos BALB C , MicroRNAs/genética , Pessoa de Meia-Idade , Mutação , Proteínas do Tecido Nervoso/genética , Prognóstico , Seleção Genética , Transativadores/genética , Ensaios Antitumorais Modelo de Xenoenxerto
19.
Chembiochem ; 20(22): 2807-2812, 2019 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-31016852

RESUMO

An unsolved mystery in biology concerns the link between enzyme catalysis and protein motions. Comparison between isotopically labelled "heavy" dihydrofolate reductases and their natural-abundance counterparts has suggested that the coupling of protein motions to the chemistry of the catalysed reaction is minimised in the case of hydride transfer. In alcohol dehydrogenases, unnatural, bulky substrates that induce additional electrostatic rearrangements of the active site enhance coupled motions. This finding could provide a new route to engineering enzymes with altered substrate specificity, because amino acid residues responsible for dynamic coupling with a given substrate present as hotspots for mutagenesis. Detailed understanding of the biophysics of enzyme catalysis based on insights gained from analysis of "heavy" enzymes might eventually allow routine engineering of enzymes to catalyse reactions of choice.


Assuntos
Álcool Desidrogenase/química , Tetra-Hidrofolato Desidrogenase/química , Bactérias/enzimologia , Biocatálise , Isótopos de Carbono/química , Domínio Catalítico , Deutério/química , Cinética , Isótopos de Nitrogênio/química , Engenharia de Proteínas
20.
Appl Environ Microbiol ; 85(15)2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31101612

RESUMO

Many aldehydes, such as furfural, are present in high quantities in lignocellulose lysates and are fermentation inhibitors, which makes biofuel production from this abundant carbon source extremely challenging. Cbei_3974 has recently been identified as an aldo-keto reductase responsible for partial furfural resistance in Clostridium beijerinckii Rational engineering of this enzyme could enhance the furfural tolerance of this organism, thereby improving biofuel yields. We report an extensive characterization of Cbei_3974 and a single-crystal X-ray structure of Cbei_3974 in complex with NADPH at a resolution of 1.75 Å. Docking studies identified residues involved in substrate binding, and an activity screen revealed the substrate tolerance of the enzyme. Hydride transfer, which is partially rate limiting under physiological conditions, occurs from the pro-R hydrogen of NADPH. Enzyme isotope labeling revealed a temperature-independent enzyme isotope effect of unity, indicating that the enzyme does not use dynamic coupling for catalysis and suggesting that the active site of the enzyme is optimally configured for catalysis with the substrate tested.IMPORTANCE Here we report the crystal structure and biophysical properties of an aldehyde reductase that can detoxify furfural, a common inhibitor of biofuel fermentation found in lignocellulose lysates. The data contained here will serve as a guide for protein engineers to develop improved enzyme variants that would impart furfural resistance to the microorganisms used in biofuel production and thus lead to enhanced biofuel yields from this sustainable resource.


Assuntos
Aldeído Redutase/química , Proteínas de Bactérias/química , Clostridium beijerinckii/química , Furaldeído/metabolismo , Aldeído Redutase/metabolismo , Proteínas de Bactérias/metabolismo , Clostridium beijerinckii/enzimologia , Inativação Metabólica
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